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4.3.11 - I²C Serial Communication

The U3 (hardware version 1.21+ only) supports Inter-Integrated Circuit (I²C or I2C) communication as the master only. I²C is a synchronous serial protocol typically used to communicate with chips that support I²C as slave devices. Any 2 digital I/O lines are used for SDA and SCL. Note that the I²C bus generally requires pull-up resistors of perhaps 4.7 kΩ from SDA to Vs and SCL to Vs, and also note that the screw terminals labeled SDA and SCL (if present) are not used for I²C.

This serial link is not an alternative to the USB connection. Rather, the host application will write/read data to/from the U3 over USB, and the U3 communicates with some other device using the serial protocol. Using this serial protocol is considered an advanced topic. A good knowledge of the protocol is recommended, and a logic analyzer or oscilloscope might be needed for troubleshooting.

The following are special channels, used with the get/put config IOTypes, to configure various parameters related to the I²C bus. See the low-level function description in Section 5.2.19 for more information about these parameters: